1. Field of the Invention
The present invention relates to an optical probe emitting light toward a measured object and receiving light reflected by the measured object, and also relates to a measuring apparatus.
2. Description of Related Art
Conventionally, an optical probe is known which emits light toward a measured object and receives light reflected by the measured object, and in addition, the optical probe is capable of changing a firing direction of the light (see, for example, Japanese Patent Laid-open Publication No. 2002-116010). A coordinate measuring device described in Japanese Patent Laid-open Publication No. 2002-116010 includes an optical probe, and the optical probe is provided with a galvano-mirror changing the firing direction of emitted light. By changing the firing direction of the light with the galvano-mirror, scanning of the measured object is performed.
In addition, the optical probe described in Japanese Patent Laid-open Publication No. 2002-116010 performs a shape measurement with a single galvano-mirror by defining emitted light, returning return light to an original optical path by the galvano-mirror, and receiving interference light which combines the return light and reference light. In contrast, an optical probe with a configuration shown in FIG. 7 is known. FIG. 7 illustrates an example of a conventional optical probe. The optical probe in FIG. 7 measures a distance between an optical probe 90 and a measured object A by a triangulation method using a pair of galvano-mirrors 93 and 94, and measures a shape of a measured object from data of a position of the optical probe 90. In such an optical probe, laser light emitted from a laser light source 91 is made parallel by a collimating lens 92 and is reflected by an incident side galvano-mirror 93 toward the measured object A. In addition, the return light reflected by the measured object A is reflected by a receiving side galvano-mirror 94, then is received at an image sensor 96 from a collecting lens 95. In this way, highly accurate measurement is possible by synchronously driving the incident side galvano-mirror 93 and the receiving side galvano-mirror 94.
In the examples shown in Japanese Patent Laid-open Publication No. 2002-116010 and FIG. 7, a galvano-mirror is used as a mechanism to perform a scanning process on the measured object by oscillating the emitted light. However, such a galvano-mirror is configured to drive a mirror with a motor so there is a limit to a size and weight reduction. Therefore, in the coordinate measuring device, for example, when using a measuring apparatus of an arm type in which an optical probe is mounted on a forefront end of a multijoint arm, weight burden is increased and operability is affected when an operator operates the optical probe by hand. In addition, for example, in a measuring apparatus of a stage-type in which a displacement mechanism is provided moving the optical probe on the stage in three axis directions and the optical probe is moved automatically, there is a load limit to the optical probe and moving accuracy is reduced when exceeding the load limit.